关键词: 刚体, 定点转动, 理论力学, 数值求解

Abstract: The landing problem of a thin cylinder is abstracted from the spinning-landing process of a washba- sin or a round plate in everyday life. This problem is analytically difficult but has a fascinating physical picture. In this paper，different approximate methods are used to gradually characterize the actual situation. The motion is shown using numerical simulation. The initial motion of a thin cylinder before it falls onto the ground can be approx-imated as a fixed point rotation and in good agreement with the reality，however，the whole motion is not fix point rotation completely. So the general motion of this rigid is studied which leads to interesting results. The initial angu- lar velocity of precession and nutation sculptured the state of motion，while force of friction plays a vital role in cau- sing energy loss of the system.

Key words: rigid, fixed point rotation, theoretical mechanics, numerical solution